The report cites issues with employment, relationships, and housing that are now affecting people in their 20s and 30s as factors that could lead to a higher risk of developing diseases like cancer, diabetes, and heart disease later in life.

Overall, the trend is "linked to long-term stress, anxiety, depression or lower quality of life", according to the report, which also found that millennials are the first generation to earn less money than their parents did at their age.

"Young people today are facing pressures that are very different to those of previous generations," said Jo Bibby, the director of strategy at the Health Foundation.

In particular, the report found that millennials are under psychological stress from insecure working hours, zero-hours contracts, underemployment, and the "gig" economy, as well as the impact of social media, which the report says adds pressure to keep up digital friendships and relationships as well as real-life connections.

In the survey of 2,000 people aged 22 to 26, just 31 percent said they had strong relationships and support networks growing up, and 46 percent said they had enough financial and family support.

Forty-nine per cent said they had emotional support from family, while 80 percent said they felt under pressure to behave a certain way because of social media.

Bibby told The Times that though there were improvements in young people's health, they could be eroded by "the precariousness and instability of the lives many young people are facing".

Michael Marmot, a professor of epidemiology and public health at University College London, added: "I agree with them that we may be storing up problems for the future, in addition to whatever problems of mental illness, crime and the like that may be happening right now."